What you need to remove a crank

Removing a bicycle crank requires a crank puller — a specialized tool that threads into the crank arm and uses leverage to separate it from the spindle. You cannot remove a crank by force alone without damaging the arm or the spindle threads. A crank puller costs between $15 and $40 at most bike shops and online retailers, and many shops will lend or rent one if you ask.

Beyond the puller, you will need an adjustable wrench or the correct socket size to turn the puller's handle, and possibly an Allen wrench or Phillips screwdriver to remove the crank bolt or cap that sits on top of the arm. Some cranks use a pinch bolt instead of a threaded cap — check your crank type before you start so you have the right tool on hand.

Key Takeaways

  • A crank puller is essential and cannot be replaced by hammering or prying — it threads into the crank arm and uses mechanical advantage to separate the arm from the spindle without damage.
  • The first step is always to remove the crank bolt or cap on top of the arm, then thread the puller into the hole left behind.
  • Turning the puller's handle slowly and steadily pulls the crank off the spindle; rushing or forcing it can strip the threads.
  • Modern cartridge bottom brackets come out as a single unit once both cranks are removed, while older square-taper systems require a separate tool to remove the spindle.

Remove the crank bolt or cap

The top of each crank arm has either a bolt or a plastic cap covering the threaded hole. If it is a bolt, use an Allen wrench (usually 8 mm) or a Phillips screwdriver to unscrew it completely and set it aside — you will need it when you reinstall the crank. If it is a plastic cap, pry it off gently with a flat screwdriver or your fingernail; the cap is not threaded and straightforward sits on top.

Once the bolt or cap is off, you will see the threaded hole where the crank puller screws in. Wipe away any dirt or grease around this hole so the puller threads seat cleanly. If the hole is clogged with old grease or debris, use a small brush or cloth to clear it.

Thread the crank puller into the arm

Screw the crank puller into the threaded hole by hand first, turning it clockwise until it is snug. Do not force it — if it resists, back it out and check that the threads are aligned straight. The puller should thread in smoothly with light hand pressure. Once it is hand-tight, use your wrench to turn it another quarter turn to may support it is seated firmly.

The puller's long handle or shaft should now extend outward from the crank arm. This is the lever that will pull the crank off. Some pullers have a handle you turn like a screw; others have a shaft that you strike gently with a hammer. Check your puller's design before you proceed.

Pull the crank off the spindle

If your puller has a turning handle, use your wrench to turn it clockwise slowly and steadily. Turn it a quarter turn at a time, then pause and check whether the crank has moved. You should feel resistance — the crank is being pulled off the tapered spindle. Keep turning in small increments until the crank separates and slides off the spindle completely.

If your puller is a shaft type, place a block of wood against the end of the shaft and strike it gently with a hammer. Do not hit hard — gentle, repeated taps work better than one hard blow. The crank will gradually slide off as the puller pushes against the spindle. Once it is loose, you can unscrew the puller by hand and remove the crank.

Do not rush this step. Forcing the crank or turning the puller too quickly can strip the threads in the crank arm, making it impossible to reinstall without damage. Patience and steady pressure work better than speed.

Remove the second crank if needed

If you are removing both cranks — for example, to replace the bottom bracket or clean the spindle — repeat the same process on the other side. The non-drive side (left side) usually comes off first and more easily because there is no chainring attached to add weight or resistance.

Once both cranks are off, the spindle is exposed. On modern bikes with a cartridge bottom bracket, the entire spindle and bearing unit comes out as one sealed piece. On older bikes with a square-taper spindle, you will need a separate bottom bracket tool to unscrew the spindle from the frame.

Reinstalling the crank

When you are ready to put the crank back on, slide it onto the spindle by hand, aligning the flat or splined surface of the spindle with the matching shape inside the crank arm. Push it on firmly until it seats all the way. Then screw the crank bolt back in by hand, and use your Allen wrench to tighten it snugly — not so tight that you strip the threads, but tight enough that the crank does not move when you pedal.

If you removed the plastic cap instead of a bolt, straightforward press the cap back on after the crank is seated. The cap is just a cover and does not hold the crank in place.

When to call a bike shop

If the crank puller does not turn smoothly, or if you feel the threads stripping, stop when ready and take the bike to a shop. Stripped threads in a crank arm usually mean the arm cannot be reused. A shop can assess whether the damage is fixable or whether you need a new crankset.

If you do not have access to a crank puller and do not want to buy one, most bike shops will remove a crank for $15 to $30 and can often lend you the tool if you want to do the reinstallation yourself at home.

Frequently Asked Questions

Can I remove a crank without a crank puller?

No. Hammering, prying, or using a regular wrench will damage the crank arm or spindle threads. A crank puller is the only safe tool for this job. If you do not own one, borrow or rent from a bike shop rather than risk breaking the crank.

What is the difference between a crank bolt and a crank cap?

A crank bolt is threaded and screws into the arm to hold the crank on the spindle. A crank cap is plastic and straightforward covers the hole — it does not hold the crank in place. Your crank will have one or the other, depending on the model and age of your bike.

How tight should the crank bolt be?

Tight enough that the crank does not move when you pedal hard, but not so tight that you strip the threads. A good rule is to tighten until you feel solid resistance, then give it one more quarter turn. If you have a torque wrench, most cranks call for 35 to 55 newton-meters, depending on the model.

Why is my crank stuck and will not come off?

Corrosion or old grease can bind a crank to the spindle. Try soaking the joint with penetrating oil (like WD-40) for an hour or two, then try the puller again. If it still will not budge, a bike shop has stronger tools and experience removing stuck cranks without damage.

Do I need to remove both cranks to clean the bottom bracket?

Yes. You cannot access the spindle or bearings without removing at least one crank, and removing both gives you full access to clean and inspect the entire bottom bracket assembly.